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CVE-2024-26752

l2tp: pass correct message length to ip6_append_data

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.19.308, 5.4.270, 5.10.211, 5.15.150, 6.1.80, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

In the Linux kernel, the following vulnerability has been resolved: l2tp: pass correct message length to ip6_append_data l2tp_ip6_sendmsg needs to avoid accounting for the transport header twice when splicing more data into an already partially-occupied skbuff. To manage this, we check whether the skbuff contains data using skb_queue_empty when deciding how much data to append using ip6_append_data. However, the code which performed the calculation was incorrect: ulen = len + skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0; ...due to C operator precedence, this ends up setting ulen to transhdrlen for messages with a non-zero length, which results in corrupted packets on the wire. Add parentheses to correct the calculation in line with the original intent.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • Linux Linux

    From 4.19.296 · fixed in 4.19.308; From 5.4.258 · fixed in 5.4.270; From 5.10.198 · fixed in 5.10.211; From 5.15.135 · fixed in 5.15.150; From 6.1.57 · fixed in 6.1.80; From 4.14.327 · fixed in 4.15; From 6.5.7 · fixed in 6.6

  • Linux Linux

    6.6

References 8

git.kernel.org